1. Field of Invention
The present invention relates to a MEMS differential actuated nano probe applicable in data storage, nanolithography and scanning probe microscope such as a scanning tunneling microscope (STM), atomic force microscope (AFM), electric force microscope (EFM), Kelvin force microscope (KFM), scanning Maxwell force microscope (SMM), frictional force microscope (FFM), lateral force microscope (LFM), magnetic force microscope (MFM), magnetic resonance force microscope (MRFM), scanning capacitance microscope (SCM), scanning thermal microscope (SThM) and scanning near-field optical microscope (SNOM), and more particularly to a MEMS (Micro Electrical Mechanical System) differential actuated nano probe.
2. Related Art
The currently available nano probe technology is based on a work platform of an atomic force microscope (AFM). The principle of the AFM uses the force lower than 1 nano Newton (about 10×−7 g) to finely sketch a structure of a sample to be tested with horizontal resolution below 10 nanometers and vertical resolution below 1 nanometer. The nano probe has cured the disadvantages regarding to diffraction limitation encountered in the conventional optical microscope, and has great contribution in micrometer and nanometer scale technology. However, most of the currently available nano probes are of passive types using an additional high-precision positioning platform to achieve topography scanning in a nanometer scale.
In an IBM journal “Journal of Research and Development”, Vol. 44, No. 3, 2000, titled “The Millipede-more than one thousand tips for future AFM data storage”, probes are driven in a thermo-mechanical way to perform reading and writing on a polymer film.
The positioning of the probes is operated via a driver that is controlled piezoelectrically or electromagnetically. The probes server to heat at fixed position. The driver drives the probes to move so as to write data on a polymer data storage medium.
In a paper published in MEMS Conference in January, 2003, titled “Micromachined arrayed DIP PEN nanolithography probes for sub-100 nm direct chemistry patterning”, disclosed an active nano probe made of Si3N4 and Au respectively having different thermal expansion coefficients. When the nano probe is heated, the nano probe deflects toward the material having a smaller thermal expansion coefficient. Furthermore, the nano probe has characteristics of moving in single direction with one degree of freedom.
In the above or other current disclosures, passive nano probes only serve to heat, without movement. Therefore, an additional actuator is needed to drive the probe to move for scanning. The active nano probes only have single direction with one degree of freedom. Both of them are not convenient in use.